Catheters are widely used for evacuating waste from post-operative wounds, particularly deep wounds. Such deep wounds may be created during spinal or other types of surgery, for example. These wounds need to be drained because waste (e.g., blood) accumulation inside the wound may result in pain and/or infection.
Various types of drains have been developed for evacuating fluids from wounds. For example, U.S. Pat. No. 3,771,527 to Ruisi discloses a surgical drainage tube which has inner and outer concentric tube portions, each having fluid apertures. A cap seals the proximal end of the outer tube portion, and the inner tube portion extends through the cap. A proximal end of the inner tube is connected to a suction source for removing fluid from the wound. Fluid from the wound enters first through the apertures in the outer tube, and then through the apertures in the inner tube where it is removed by the suction. The cap is made of a penetrable, self-sealing material, such as pregnable latex, which allows a hypodermic needle to be inserted therethrough to introduce a fluid into the outer tube, such as an antibiotic solution or a sterile flushing solution. One potential drawback of this arrangement, however, is that medicine injected into the catheter may be evacuated through the apertures in the inner tube. This may result in wasted medicine, and it may make it difficult to provide a steady supply of medicine into the wound, for example.
U.S. Patent Application Publication No. 2004/0030281 is directed to an infusion and aspiration catheter assembly for a surgical wound site. The catheter assembly includes an infusion catheter and an aspiration catheter, each having ports located at the distal end of thereof. The infusion catheter extends through the aspiration catheter and beyond the distal end thereof. This is done so that the distal end of the infusion catheter can be placed in a different location than the distal end of the aspiration catheter, such as on opposing sides of a patient's knee. The infusion catheter is connected at the proximal end to a pump, which is connected to a medication reservoir. The medicinal fluid delivered via the infusion catheter may be an analgesic, anesthetic, antibiotic, antiseptic, anticoagulant, anti-inflammatory, or combinations thereof. Moreover, the aspiration catheter is connected to an aspiration reservoir, and suction created by a suction pump connected thereto causes excess fluid to be removed from the wound site. Similar infusion/drain catheter systems for delivery of pain medication to a specific location are disclosed in U.S. Pat. Nos. 6,325,788; 5,616,121; and 6,569,839, for example.
Another example is disclosed in U.S. Pat. No. 3,823,720 to Tribble. This patent discloses a surgical drain which includes a drainage catheter and an irrigation catheter wrapped within a nylon net. The irrigation catheter may be used either for introducing an irrigating fluid, or for an antibiotic or other medicinal liquid. U.S. Pat. No. 5,558,634 to Mitchell discloses an apparatus for the removal of viscoelastic material from an eye chamber which includes an irrigation lumen and an aspiration lumen. In one embodiment, the irrigation lumen is within the aspiration lumen and extends outwardly therefrom.
A closed wound drainage system is disclosed in U.S. Patent Application Publication No. 2004/0054338. A flexible, porous pouch is inserted into a wound. Exudates are removed via the pores in the pouch through an aspiration tube, which is connected to a portable drain/suction unit. Another tube may also be used for pumping medications, such as antibiotics, into the pouch. Moreover, the pouch may also include beads and fillers therein which are antibacterial in nature. The pouch and tube(s) are sealed in the wound by a flexible sealing gel, such as a hydro-colloid, silicon, or a lyogel.
One drawback of such prior art catheter systems which are connected to an external medicine source (e.g., a pump) for receiving medicine is that this requires multiple tubes to be connected to the catheter, which increases the chances of tangling the tubes. Moreover, a separate pump may require relatively frequent monitoring, and it may also limit the patient's mobility and/or movement. Further, medication tubes which run to an external medicine pump may unknowingly be bent or crimped, which undesirably restricts the flow of medicine to the wound.